/*
 * Copyright 2002-2010 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using Spring.Expressions;

namespace Spring.Validation;

/// <summary>
/// Abstract base class that should be extended by all
/// validation actions.
/// </summary>
/// <remarks>
/// <p>
/// This class implements template <c>Execute</c> method
/// and defines <c>OnValid</c> and <c>OnInvalid</c> methods that
/// can be overriden
/// by specific validation actions.
/// </p>
/// </remarks>
/// <author>Aleksandar Seovic</author>
public abstract class BaseValidationAction : IValidationAction
{
    private IExpression when;

    /// <summary>
    /// Initializes a new instance of the <see cref="BaseValidationAction"/> class.
    /// </summary>
    public BaseValidationAction()
    {
    }

    /// <summary>
    /// Gets or sets the expression that determines if this validator should be evaluated.
    /// </summary>
    /// <value>The expression that determines if this validator should be evaluated.</value>
    public IExpression When
    {
        get { return when; }
        set { when = value; }
    }

    /// <summary>
    /// Executes the action.
    /// </summary>
    /// <param name="isValid">Whether associated validator is valid or not.</param>
    /// <param name="validationContext">Validation context.</param>
    /// <param name="contextParams">Additional context parameters.</param>
    /// <param name="errors">Validation errors container.</param>
    public virtual void Execute(bool isValid, object validationContext, IDictionary<string, object> contextParams, IValidationErrors errors)
    {
        if (EvaluateWhen(validationContext, contextParams))
        {
            if (isValid)
            {
                OnValid(validationContext, contextParams, errors);
            }
            else
            {
                OnInvalid(validationContext, contextParams, errors);
            }
        }
    }

    /// <summary>
    /// Called when associated validator is valid.
    /// </summary>
    /// <param name="validationContext">Validation context.</param>
    /// <param name="contextParams">Additional context parameters.</param>
    /// <param name="errors">Validation errors container.</param>
    protected virtual void OnValid(object validationContext, IDictionary<string, object> contextParams, IValidationErrors errors)
    {
    }

    /// <summary>
    /// Called when associated validator is not valid.
    /// </summary>
    /// <param name="validationContext">Validation context.</param>
    /// <param name="contextParams">Additional context parameters.</param>
    /// <param name="errors">Validation errors container.</param>
    protected virtual void OnInvalid(object validationContext, IDictionary<string, object> contextParams, IValidationErrors errors)
    {
    }

    /// <summary>
    /// Evaluates 'when' expression.
    /// </summary>
    /// <param name="rootContext">Root context to use for expression evaluation.</param>
    /// <param name="contextParams">Additional context parameters.</param>
    /// <returns><c>True</c> if the condition is true, <c>False</c> otherwise.</returns>
    protected bool EvaluateWhen(object rootContext, IDictionary<string, object> contextParams)
    {
        if (When == null)
        {
            return true;
        }

        return Convert.ToBoolean(When.GetValue(rootContext, contextParams));
    }
}
